I'm confused. You said you were J1 and L1 in 2024? or 2023?
If you were J1 other than J1 student, you were an "exempt individual" (for the Substantial Presence Test) for your days on J1 in your first two calendar years, 2021 and 2022. You were not an "exempt individual" for any days on J1 in 2023 or 2024. So you passed the Substantial Presence Test for 2023 and you were a resident alien for all of 2023 (and 2024).
Are you asking about the 36-month tax exemption for "teachers, professors, and researchers" from Article 19 of the US-China tax treaty? If so, see the Publication 519 section "Students, Apprentices, Trainees, Teachers, Professors, and Researchers Who Became Resident Aliens" for how to claim the treaty tax exemption as a resident alien. It says you should give a W9 to the employer to avoid tax withholding. If your employer reported the income as taxable on your W2, you would report the income as normal, and then report the tax-exempt amount as a negative number on 1040 Schedule 1 line 8z.
